Furnace troubleshooting

Top Lennox® Furnace Error Codes (and What They Mean)

While your Lennox® furnace cannot talk to you, it does have a process to communicate a furnace error.

Its motherboard has twin LED lights that can show a fault code. Based on the fault, your heater may display solid or flashing lights.

Although there are some elementary furnace adjustments you can do on your own, most repairs are best left to HVAC technicians. When your heating system refuses to turn on or deliver heated air, contact Mustang Mechanical at 972-445-9504 for professional furnace repair in Grand Prairie.

Our technicians will rapidly determine and fix the breakdown, even if you don’t use a Lennox heating system. We can service any kinds or models—and get the heat reintroduced to your home fast.


What Does the Flashing Light on My Heating System Mean?

Your heater relies on lights to flash code when it is malfunctioning. It also works this system to tell you it’s heating correctly.

Correct function includes:

  • Both lights flash slowly—heating system heating properly.
  • Concurrent fast flash—furnace is beginning to call for heat.

If you notice a lone light going on and off slowly and the other flashing rapidly, your furnace may be having a low flame signal. This can happen even when your heater is running properly. It signifies the flame sensing rod may be dirty or in the bad spot on the burner. Reach out to us at 972-445-9504 for help.

Here are several other of the most common problems for Lennox furnaces.

Heater Refuses to Start

Here are many of the light patterns you could see when your furnace will not or keep running. Most of these errors need to be handled by a specialist, for instance from Mustang Mechanical.

  1. The duo of LED lights aren’t lit. This indicates your heating system might not have power. Go to the breaker box to ensure the heating system fuse hasn’t triggered. You should reset the fuse if it has moved into the “off” spot. If it promptly turns off after a subsequent reset, leave the breaker alone and get in touch with us us at 972-445-9504.
  2. One light is solid and the other is flickering slowly. This shows the flame rollout switch is possibly not working right. The part is an important safety device that aids in avoiding fires and carbon monoxide. You shouldn’t seek to repair this malfunction without professional help.
  3. A single light is flickering rapidly and the other is flashing slowly. This often indicates power polarity has been transposed. Your heater might have a wiring fault that calls for professional support from Mustang Mechanical.
  4. The duo of lights are flashing slowly. This signifies your heating system’s blower motor possibly isn’t running. This piece distributes hot air from the HVAC system into your home. We can aid in pinpointing what’s causing a problem with this part.
  5. An individual light is blinking slowly and the other is flashing quickly. This indicates your heater may have not enough voltage or a short circuit. Contact our specialists at 972-445-9504 for support.
  6. One light is flashing on, on and off while the other flickers on, off, on. This indicates there could be trouble with your heating system’s control panel or wiring. Mustang Mechanical can locate the fault and repair it.
  7. The pair of lights display every other slow blinks. This means your HVAC system possibly has a flame failure. There might be a problem with its gas supply, gas valve or ignitor control. Get in touch with us at 972-445-9504 for support.
  8. A single light flickers slowly while the other stays solid. This often means your HVAC system’s limit switch is malfunctioning. The switch prevents your heating system from getting too hot. Contact the specialists at Mustang Mechanical for assistance.

Heating System Blower Runs But No Heat

Here’s what may be wrong when you notice your heating equipment’s blower fan running, but you aren’t gaining any heat.

  • The duo of lights are showing alternating fast flashes. This indicates your furnace ignitor may be broken. This part kindles fuel in your furnace to create heat and should be fixed by a technician from Mustang Mechanical.

Depend on Us for Skilled Furnace Repair

When you need to have your heater repaired quickly, turn to the technicians at Mustang Mechanical. Our techs will repair the problem right away and have your rooms feeling relaxing again in a short time. Call us at 972-445-9504 or contact us online to schedule an appointment now.

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